Agriculture Reference
In-Depth Information
End of flowering
Potential hurd yield (t MS/ha) = (Σ
temperatures − 100 − 250)/120)
The end of flowering is defined by the fertiliza-
tion of the last female flowers. This stage
marks the end of the growth phase and deter-
mines the yield in hurds, as well as inducing
the subsequent phases of hurd and seed
maturation.
The physiological maturity of the seeds is
obtained approximately 40 days after full flow-
ering. The timing of the harvest will, however,
need to take into account the humidity of the
seeds and the capacity of the driers. These fac-
tors may result in harvesting being delayed
(see Chapter 6, Hemp cultivation in France
and Chapter 8, Agricultural Economics). In
fact, seed humidity levels are very dependent
on the state of cultivation and, in particular, the
presence of leaves. This last factor is depend-
ent on the hydration of the crop and its nitro-
gen fertilization.
The sum total of the temperatures is to be cal-
culated from the day the seeds are sown until
the variety has finished flowering. For any given
varietal at a known latitude (zone of cultivation),
this date will be known and predictable.
NB: The '100' corresponds with the sum of
the temperatures required at emergence. During
this period, there is no growth of the crop (that
is to say - no yield in agricultural terms).
The '250' corresponds with the sum of
the temperatures recorded during the
implantation phase (growth of the root sys-
tem and development of the first three pairs
of leaves). During this time, the agricultural
growth and yield is poor and it is possible to
ignore the small quantity of hurd produced.
The active growth starts at the end of
the implantation phase and it is only at this
point that the sum of the temperatures
starts to influence yield.
The agricultural yield must be increased
by 15% to take into account the average
humidity levels and the payment schemes that
reflect this.
Calculating crop yields
The potential hurd yield of a hemp crop can,
under normal circumstances, be calculated
using the following formula:
Note
The majority of molecules described in the text are indexed, together with their bibliographic links, in the
Pub Chem database of the National Center for Biotechnology Information (NCBI, USA;
http://pubchem.
